This invention relates generally to food processors and, more particularly, to a concentric removable drive arrangement for food processing tools which, in its preferred form, permits a plurality of interchangeable food processing heads to be simply fitted onto a single drive extension such that only a single drive extension is required and the food processing tools can be packaged and stored in a compact form.
Food processors are a well known convenience for preparing food by slicing, grating, shredding or similar food processing operations. A conventional form of food processor includes a working bowl having a motor driven shaft projecting upwardly in the center of the bowl. A variety of food processing tools are coupled to the shaft and rotated to perform a corresponding variety of food processing operations as required by the operator of the food processor.
A detachable bowl cover is secured to the working bowl during operation of the food processor. The bowl cover defines a feed tube for introducing food items to be processed through the bowl cover into the bowl. Foods to be processed are placed into the feed tube and then pushed through the tube into engagement with a processing tool by means of a food pusher which is formed to be slidingly inserted into the feed tube.
The food processing tools each typically comprise a horizontal disk-like member formed of sheet metal, typically stainless steel, which is fixedly mounted on an extension shaft. The extension shafts of the food processing tools are formed such that they can be removably engaged with the driven shaft projecting upwardly in the center of the working bowl. Accordingly, when a food processing tool of this design is to be changed, the tool extension shaft is removed from the motor driven shaft and the extension shaft of the next tool to be utilized is then coupled to the motor driven shaft. Two problems associated with such prior art food processing tools have been recognized and addressed in the prior art.
Initially, the cutting length or effective food processing length of a disk-like member or disk over which food processing can be effected was limited by the way that the extension shaft was mounted to the disk. In particular, a centralized head of the extension shaft was concentrically mounted to the disk preventing the central portion of the disk from being used for food processing. Hence, the centralized head mounted to the disk limited the maximum cutting length or effective food processing length which could be provided by a given diameter disk. It was desired to be able to expand the food processing length to a maximum for each disk such that the food processing length would extend substantially from the center of the disk to its periphery, i.e., be approximately equal to the radius of the disk.
The extension of the effective processing length for a disk to approximately the radius of the disk was addressed by James E. Williams in U.S. Pat. No. 4,227,655. In Williams' food processing tool, the extension shaft, referred to as an elongated hub, extends between the motor driven shaft and an associated disk-like cutting member. To lengthen the effective processing length of a disk, a head of the elongated hub is offset radially from the axis of the motor driven shaft such that the head of the hub revolves around the axis of rotation of the motor driven shaft. By mounting the offset head of the elongated hub at a location which is radially offset from the center of the disk, food processing means can be provided on the disk from near its center to its periphery. Williams thus offered a solution to one problem of food processing tools by enabling larger food processing lengths and, hence, larger sized feed tubes to be used for a given diameter disk. In Williams' solution, however, each cutting member still had a full-length extension shaft secured to the member to form a food processing tool.
This leads to the second problem, namely, the fixedly-mounted full-length extension shafts which require a large amount of space for packaging or storage of the tool. It is apparent that once the offset head of the elongated hub of Williams or the centralized head of the concentric extension shaft of the earlier cutting tools is secured to a disk to form a stable food processing tool, the tool formed thereby effectively occupies a three dimensional box having a square base with sides equal in length to the diameter of the disk and a height equal to the length of the extension shaft or elongated hub.
The second problem has also been addressed in the prior art and two solutions have been patented with James E. Williams being a named inventor in U.S. Pat. Nos. 4,456,184 and 4,458,848. Both of these later Williams' patents are concerned with providing a food processing tool having a removable food processing head such that a plurality of food processing heads can be provided for interchangeable use with a single elongated hub. Both of Williams' later patents maintain the offset head mounting arrangement of his earlier patent such that the effective length of the processing tool can extend from near the center of a disk to its periphery.
Unfortunately, apparently due to the forces applied to the disk as a result of the offset attachment of the hub head to the disk, the food processing disks or heads must be securely interlocked to the elongated hub. Accordingly, in both the later Williams' patents, rather complicated arrangements are provided for interlocking the interchangeable food processing heads to the elongated hub. These interlocks appear to be a compromise for retaining the offset head of an elongated hub for mounting a disk or food processing head yet permitting the head to be removable and hence, interchangeable on the hub with other heads. The interlocks thus permit detachable engagement of the food processing heads with the offset head of the elongated hub, but are mechanically complex requiring considerable apparatus making the food processing tools more difficult and costly to manufacture than their simplier, fixed-head predecessor designs.
It is thus apparent that the need exists for a simple, removable head food processor tool which can extend the effective food processing length to approximately the radius of a disk-like member of the removable head and which occupies less space for packaging and storage without requiring complex and costly interlocks to hold the removable head to a drive extension.